2006 Mercruiser 4.3 no power to Fuel Pump

[1tman1]

Did you check your antisiphon valve ?

No. We did not. But the symptoms seemed to be pointing (eventually) to the Fuel Pump. Where is the Anti-Siphon Valve? And how would one check it?
Thanks

 

[1tman1]

Something that doesn't work and then mysteriously works is cause for concern as that mystery repair may come back to bite you when you leaste expect it -- like miles from the ramp!I suggest you really look into this further.

Thanks, but I wouldn’t have said it now mysteriously works? We spent a fair bit of time eliminating a bunch of potential reasons, and the conclusion we came to was that It seemed that there was either a Vacuum in the Fuel Line, or there was something stuck inside the Fuel Pump. The Boat had been sitting a while, and was running 100% when last used. We haven’t field tested it yet, but it’s running as well as ever now in the tank. Will be field testing it tomorrow on the lake, not too far from land, with Oars on hand
Someone else suggested checking the Anti-Siphon Valve? But this hadn’t come up as a potential issue from the symptoms we were experiencing.
Cheers

 

[Scott06]

No. We did not. But the symptoms seemed to be pointing (eventually) to the Fuel Pump. Where is the Anti-Siphon Valve? And how would one check it?
Thanks

Antisiphon valve is in fuel line on top of fuel tank. It takes a slight cracking pressure to open. Idea is it will prevent a leak in fuel line from siphoning the fuel tank into the bilge… problem is they can stick and not open impeding fuel flow. If the fuel pump is running but no fuel was flowing woukd take it off and make sure it is clean and opening properly/ easily

 

[H20Rat]

Also, oil pressure switch failures can be intermittent. You may have jostled something enough when you took it out that it works, for a while.